A display panel including glass substrates in a liquid crystal display device or an organic EL display device includes two glass substrates that have certain compositions thereon and are bonded to each other with a certain clearance therebetween. An edge portion of such a display panel is connected to a flexible printed circuit board on which a drive circuit is mounted to receive supply of power voltage and display signals from external devices. An example of a configuration of connecting the flexible printed circuit board to the edge portion of the display panel is described in Patent document 1.
Patent document 1 describes an electronic component connection structure in which a first outer connection terminal disposed on a second transparent substrate is connected to a first connection terminal installed in a first FPC. The connection structure includes a first alignment mark formed on a first surface of the second transparent substrate having the first outer connection terminal and made of ITO, and an auxiliary mark formed on a second surface of the second transparent substrate and made of an opaque film. The second surface is a rear surface side of the first surface. The auxiliary mark corresponds to the first alignment mark.